[hagen1778]

We use the same approach in time series database I'm working on. While file creation and fsync aren't atomic, rename [1] syscall is. So we create a temporary file, write the data, call fsync and if all is good - rename it atomically to be visible for other users. I had a talk about this [2] a few month ago.

[1] https://man7.org/linux/man-pages/man2/rename.2.html

[2] https://www.youtube.com/watch?v=1gkfmzTdPPI

[yencabulator]

You can't atomically allocate a unique identifier (e.g. next step of a counter) with rename, it'll overwrite. That's what the link(2) is for.